Apparatus and method for transmitting acknowledgement information in a tdd communication system

ABSTRACT

Methods and apparatus are described for a User Equipment (UE) configured with multiple cells in the downlink of a time division duplex communication system to transmit HARQ-ACK information in a Physical Uplink Shared CHannel (PUSCH), to map HARQ-ACK bits transmitted in a PUSCH to information regarding correct or incorrect detections of data transport blocks in different cells and different transmission time intervals, and to provide a same understanding with an intended reception point of the information represented by HARQ-ACK bits the UE transmits in a PUSCH.

PRIORITY

The present application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/476,975, which was filed in the United States Patent and Trademark Office on Apr. 19, 2011, the entire disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to wireless communication systems, and more particularly, to the transmission of acknowledgement information in an uplink of a communication system.

2. Description of the Art

A communication system includes a DownLink (DL) that conveys transmission signals from a Base Station (BS or NodeB) to User Equipments (UEs) and an UpLink (UL) that conveys transmission signals from UEs to the NodeB.

More specifically, a UL conveys transmissions of data signals carrying information content, transmissions of control signals providing control information associated with transmissions of data signals in a DL, and transmissions of Reference Signals (RSs), which are commonly referred to as pilot signals. A DL also conveys transmissions of data signals, control signals, and RSs. UL signals may be transmitted over clusters of contiguous REs using a Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing (DFT-S-OFDM) method. DL signals may be transmitted using an OFDM method.

UL data signals are conveyed through a Physical Uplink Shared CHannel (PUSCH) and DL data signals are conveyed through a Physical Downlink Shared CHannel (PDSCH).

In the absence of a PUSCH transmission, a UE conveys UL Control Information (UCI) through a Physical Uplink Control CHannel (PUCCH). However, when a UE has a PUSCH transmission, it may convey UCI with data through the PUSCH.

DL control signals may be broadcast or sent in a UE-specific nature. Accordingly, UE-specific control channels can be used, among other purposes, to provide UEs with Scheduling Assignments (SAs) for PDSCH reception (DL SAs) or PUSCH transmission (UL SAs). The SAs are transmitted from the NodeB to respective UEs using DL Control Information (DCI) formats through respective Physical DL Control CHannels (PDCCHs).

The NodeB may configure a UE through higher layer signaling, such as Radio Resource Control (RRC) signaling, a PDSCH, and a PUSCH Transmission Mode (TM). The PDSCH TM or PUSCH TM is respectively associated with a DL SA or a UL SA, and defines whether the respective PDSCH or PUSCH conveys one data Transport Block (TB) or two data TBs.

PDSCH or PUSCH transmissions are either scheduled to a UE by a NodeB through higher layer signaling or through physical layer signaling (e.g., a PDCCH) using a respective DL SA or UL SA, or correspond to non-adaptive retransmissions for a given Hybrid Automatic Repeat reQuest (HARQ) process. Scheduling by higher layer signaling is referred to as Semi-Persistent Scheduling (SPS), and scheduling by a PDCCH is referred to as dynamic. A PDCCH may also be used to release an SPS PDSCH. If a UE fails to detect a PDCCH, this event is referred to as Discontinuous Transmission (DTX).

The UCI includes ACKnowledgment (ACK) information associated with a HARQ process (HARQ-ACK). The HARQ-ACK information may include multiple bits indicating the correct or incorrect detection of multiple data TBs. Typically, a correct detection of a data TB is indicated by a positive acknowledgment (i.e., an ACK) while an incorrect detection is indicated by a Negative ACK (NACK). If a UE misses (e.g., fails to detect) a PDCCH, it may explicitly or implicitly (absence of a signal transmission) indicate DTX (tri-state HARQ-ACK information) or both a DTX and an incorrect reception of a TB can be represented by a NACK (in a combined NACK/DTX state).

In Time Division Duplex (TDD) systems, DL and UL transmissions occur in different Transmission Time Intervals (TTIs), which are referred to as subframes. For example, in a frame including 10 subframes, some the subframes may be used for DL transmissions and some may be used for UL transmissions.

If a PDSCH conveys one data TB, respective HARQ-ACK information typically consists of one bit that is encoded as a binary ‘1’, if the TB is correctly received (i.e., an ACK value), and as a binary ‘0’, if the TB is incorrectly received (i.e., a NACK value). If a PDSCH conveys two data TBs, in accordance with a Single-User Multiple Input Multiple Output (SU-MIMO) transmission method, respective HARQ-ACK information typically consists of two bits [o₀ ^(ACK)o₁ ^(ACK)] with o₀ ^(ACK) for a first TB and o₁ ^(ACK) for a second TB.

FIG. 1 illustrates a conventional TTI for a PUSCH or a PUCCH.

Referring to FIG. 1, a TTI consists of one subframe including two slots for PUSCH 110A or PUCCH 110B transmission. Each slot 120A and 120B includes M_(symb) ^(UL) symbols 130A used for signaling data or HARQ-ACK information in a PUSCH, or N_(symb) ^(UL) symbols 130B used for HARQ-ACK information in a PUCCH, and Reference Signals (RS) 140A or 140B, which are used for channel estimation and coherent demodulation of received data or HARQ-ACK information. The transmission BandWidth (BW) consists of frequency resource units that are referred to as Physical Resource Blocks (PRBs). Each PRB consists of N_(sc) ^(RB) sub-carriers, or Resource Elements (REs). For PUSCH transmission, a UE is allocated M_(PUSCH) PRBs for a total of M_(sc) ^(PUSCH)=N_(PUSCH)·N_(sc) ^(RB) REs 150A. For PUCCH transmission, a UE is allocated 1 PRB 150B, which may be in two different BW locations in each of the two subframe slots.

FIG. 2 illustrates a conventional HARQ-ACK transmission structure in a PUCCH subframe slot.

Referring to FIG. 2, HARQ-ACK bits b 210 modulate 220 a Constant Amplitude Zero Auto-Correlation (CAZAC) sequence 230, for example, using Binary Phase Shift Keying (BPSK) with b=b₀ or Quaternary Phase Shift Keying (QPSK) with b=(b₀, b₁). The modulated CAZAC sequence is then transmitted after performing an Inverse Fast Frequency Transform (IFFT) 240. The RS is transmitted through a non-modulated CAZAC sequence after performing an IFFT 250.

FIG. 3 is a block diagram illustrating of a conventional transmitter for a PUCCH.

Referring to FIG. 3, a CAZAC sequence 310 can be used without modulation for an RS or with modulation for HARQ-ACK information. The transmitter in the FIG. 3 includes a selector 320, a sub-carrier mapper 330, an IFFT unit 340, a Cyclic Shifter 350, a Cyclic Prefix (CP) inserter 360, and a filter 370 for time windowing. For sub-carrier mapping in the sub-carrier mapper 330, the selector 320 selects a first PRB and a second PRB for transmission of the CAZAC sequence in a first slot and a second slot, respectively. Subsequently, the IFFT unit 340 performs IFFT, and the Cyclic Shifter 350 applies a Cyclic Shift (CS) to the output of the IFFT unit 340. A CP and filtering are applied by the CP inserter 360 and the filter 370. Thereafter, the signal 380 is transmitted. Additional transmitter circuitry such as a Digital-to-Analog Converter (DAC), analog filters, amplifiers, transmitter antennas, etc., are not shown for brevity.

FIG. 4 is a block diagram illustrating a conventional receiver diagram for a PUCCH.

Referring to FIG. 4, the receiver includes a filter 420 for time windowing, a CP remover 430, a CS restorer 440, a Fast Fourier Transform (FFT) unit 450, a sub-carrier de-mapper 460, a selector 465, and a multiplier 470. An antenna (not shown) receives an analog signal and after further processing units (such as filters, amplifiers, frequency down-converters, and Analog-to-Digital Converters (ADCs) that are not shown for brevity), a digital received signal 410 passes through the filter 420 and the CP remover 430. Subsequently, a CS is restored by the CS restorer 440, the FFT 450 unit applies FFT, for sub-carrier demapping in the sub-carrier demapper 460, a selector 465 selects REs in a first PRB and a second PRB in a first slot and in a second slot, respectively, and a multiplier correlates 470 the REs with a replica of a CAZAC sequence 480. The output 490 may then be passed to a channel estimation unit, such as a time-frequency interpolator, when a subframe symbol conveys a RS, or to a detection unit, when a subframe symbol conveys a HARQ-ACK signal.

Different CSs of a same CAZAC sequence provide orthogonal CAZAC sequences and can be allocated to different UEs to achieve orthogonal multiplexing of HARQ-ACK signal transmissions in the same PRB. If T_(s) is a symbol duration, the number of such CSs is approximately └T_(s)/D┘, where D is a channel propagation delay spread and └ ┘ is a floor function that rounds a number to its immediately lower integer.

In addition to orthogonal multiplexing of HARQ-ACK signals and an RS in a same PRB using different CS of a CAZAC sequence, orthogonal multiplexing may also be in the time domain using Orthogonal Covering Codes (OCC). For example, in FIG. 2, a HARQ-ACK signal can be modulated by a length-4 OCC, such as a Walsh-Hadamard (WH) OCC, while an RS can be modulated by a length-3 OCC, such as a DFT OCC (not shown). When using an OCC, the multiplexing capacity per PRB increases by a factor of 3 (determined by the OCC with the smaller length). The sets of WH OCCs {W₀, W₁, W₂, W₃}, and DFT OCCs {D₀, D₁, D₂}, are respectively

$\begin{bmatrix} W_{0} \\ W_{1} \\ W_{2} \\ W_{3} \end{bmatrix} = \begin{bmatrix} 1 & 1 & 1 & 1 \\ 1 & {- 1} & 1 & {- 1} \\ 1 & 1 & {- 1} & {- 1} \\ 1 & {- 1} & {- 1} & 1 \end{bmatrix}$

and

$\begin{bmatrix} D_{0} \\ D_{1} \\ D_{2} \end{bmatrix} = {\begin{bmatrix} 1 & 1 & 1 \\ 1 & ^{{- j}\; 2\; {\pi/3}} & ^{{- j}\; 4\; {\pi/3}} \\ 1 & ^{{- j}\; 4\; {\pi/3}} & ^{{- j}\; 2\; {\pi/3}} \end{bmatrix}.}$

Table 1 presents a mapping for a PUCCH resource n_(PUCCH) used for a HARQ-ACK signal and an RS transmission to an OCC n_(oc), and a CS α, assuming 6 CS per symbol and a length-3 OCC (with 3 CS used for each OCC). If all resources within a PUCCH PRB are used, resources in an immediately next PRB can be used.

TABLE 1 PUCCH Resource Mapping to OCC and CS. OCC n_(oc) for a HARQ-ACK and for an RS CS α W₀, D₀ W₁, D₁ W₃, D₂ 0 n_(PUCCH) = 0 n_(PUCCH) = 6 1 n_(PUCCH) = 3 2 n_(PUCCH) = 1 n_(PUCCH) = 7 3 n_(PUCCH) = 4 4 n_(PUCCH) = 2 n_(PUCCH) = 8 5 n_(PUCCH) = 5

A PDCCH is transmitted in elementary units that are referred to as Control Channel Elements (CCEs). Each CCE may consist of 36 REs. UEs are informed of a total number of CCEs, N_(CCE) through a transmission of a Physical Control Format Indicator CHannel (PCFICH) by a serving NodeB. The PCFICH indicates a number of OFDM symbols used for PDCCH transmissions in a respective DL subframe. A one-to-one mapping can exist between PUCCH resources (PRB, CS, OCC) for HARQ-ACK signal transmission and PDCCH CCEs. For example, if a single PUCCH resource is used for HARQ-ACK signal transmission, it may be derived from the CCE with the lowest index in a PDCCH conveying a respective DL SA.

In TDD systems, DL and UL transmissions occur in different subframes and M≧1 DL subframes may be associated with a single UL subframe. The association is in the sense that HARQ-ACK information generated in response to reception of data TBs in M≧1 DL subframes is transmitted in a single UL subframe. This set of M≧1 DL subframes is commonly referred to as a bundling window. Denoting a DL subframe index by m=0, 1, . . . , M−1, a number of CCEs for a PCFICH value of p (N₀=0) by N_(p), and a first PDCCH CCE of a DL SA in subframe m by n_(CCE)(m), a PUCCH resource indexing for HARQ-ACK signal transmission can be as described below.

A UE first selects a value pε{0, 1, 2, 3} providing N_(P)≦n_(CCE)(m)<N_(p+1) and then considers n_(PUCCH,m)=(M−m−1)×N_(p)+m×N_(p+1)+n_(CCE)(m)+N_(PUCCH) as a PUCCH resource available for HARQ-ACK signal transmission in response to a DL SA in DL subframe m, where N_(p)=max {0,└[N_(RB) ^(DL)×(N_(sc) ^(RB)×p−4)]/36 ┘}, N_(PUCCH) is an offset informed to a UE by higher layer signaling, N_(sc) ^(RB) is a number of sub-carriers and N_(RB) ^(DL) is a number of PRBs in the DL operating BW.

HARQ-ACK information in a PUCCH may be conveyed with several methods including HARQ-ACK time-domain bundling and HARQ-ACK multiplexing using channel selection (referring to a selection of a PUCCH resource from a set of available PUCCH resources). In both cases, HARQ-ACK spatial-domain bundling applies where a UE generates an ACK, only if it receives all data TBs in a PDSCH correctly, and generates a NACK otherwise.

With HARQ-ACK time-domain bundling, a UE generates an ACK, only if it receives all TBs in a bundling window correctly, and generates a NACK otherwise. Therefore, HARQ-ACK time-domain bundling results in unnecessary retransmissions as a NACK is sent even when the UE correctly receives some of the TBs in a bundling window.

With HARQ-ACK multiplexing using channel selection, a UE conveys HARQ-ACK information for each DL subframe in a bundling window by selecting a PUCCH resource from a set of possible resources and by modulating the HARQ-ACK signal using QPSK modulation.

Table 2 describes HARQ-ACK multiplexing using channel selection for M=3 in a TDD system with a single DL cell and a single UL cell. Specifically, a UE modulates a HARQ-ACK signal using the QPSK constellation point and selects one of PUCCH resources n_(PUCCH)(0), n_(PUCCH)(1), or n_(PUCCH)(2), which are respectively determined by a first CCE of a respective PDCCH conveying a DL SA in a respective first, second, or third DL subframe (if any).

Explicit DTX indication is possible by including a Downlink Assignment Index (DAI) Information Element (IE), which indicates an accumulative number of PDSCH transmission(s) to a UE (the DAI IE is a counter within a bundling window), in DCI formats conveying DL SAs.

TABLE 2 HARQ-ACK Multiplexing with Channel Selection for M = 3 DL Subframes Entry HARQ-ACK(0), HARQ-ACK(1), Number HARQ-ACK(2) n_(PUCCH) Constellation 1 ACK, ACK, ACK n_(PUCCH, 2) 1, 1 2 ACK, ACK, NACK/DTX n_(PUCCH, 1) 1, 1 3 ACK, NACK/DTX, ACK n_(PUCCH, 0) 1, 1 4 ACK, NACK/DTX, NACK/DTX n_(PUCCH, 0) 0, 1 5 NACK/DTX, ACK, ACK n_(PUCCH, 2) 1, 0 6 NACK/DTX, ACK, NACK/DTX n_(PUCCH, 1) 0, 0 7 NACK/DTX, NACK/DTX, ACK n_(PUCCH, 2) 0, 0 8 DTX, DTX, NACK n_(PUCCH, 2) 0, 1 9 DTX, NACK, NACK/DTX n_(PUCCH, 1) 1, 0 10 NACK, NACK/DTX, NACK/DTX n_(PUCCH, 0) 1, 0 11 DTX, DTX, DTX N/A N/A

When HARQ-ACK information is transmitted in a PUSCH, it is encoded depending on a number of HARQ-ACK bits being conveyed. Assuming HARQ-ACK spatial-domain bundling, each HARQ-ACK bit conveys an outcome of each PDSCH reception and is encoded as a binary ‘1’, if the respective TB(s) are correctly received (i.e., an ACK), and is encoded as a binary ‘0’, if the respective TB(s) are incorrectly received (i.e., a NACK). Therefore, an individual HARQ-ACK bit is conveyed for each PDSCH reception. When HARQ-ACK information consists of o=1 bit o₀ ^(ACK), it is encoded using repetition coding. When HARQ-ACK information consists of o=2 bits [o₀ ^(ACK)o₁ ^(ACK)], it is encoded using a (3, 2) simplex code, as described in Table 3 for Q_(m) data modulation bits, where o₂ ^(ACK)=(o₀ ^(ACK)+o₁ ^(ACK))mod 2.

TABLE 3 Encoding for 1 and 2 HARQ-ACK Information Bits. Encoded Q_(m) HARQ-ACK - 1 bit Encoded HARQ-ACK - 2 bits 2 [o₀ ^(ACK) y] [o₀ ^(ACK) o₁ ^(ACK) o₂ ^(ACK) o₀ ^(ACK) o₁ ^(ACK) o₂ ^(ACK)] 4 [o₀ ^(ACK) y x x] [O₀ ^(ACK) O₁ ^(ACK) X X O₂ ^(ACK) O₀ ^(ACK) X X O₁ ^(ACK) O₂ ^(ACK) X X] 6 [o₀ ^(ACK) y x x x x] [o₀ ^(ACK) o₁ ^(ACK) x x x x o₂ ^(ACK) o₀ ^(ACK) x x x x o₁ ^(ACK) o₂ ^(ACK) x x x x]

When HARQ-ACK information corresponds to a possible reception of more than 2 PDSCHs (assuming HARQ-ACK spatial-domain bundling) and consists of respective 3≦o^(ACK)≦11 bits, the coding may be by a (32, o^(ACK)) Reed-Mueller (RM) block code. Denoting the HARQ-ACK information bits by o₀ ^(ACK) o^(ACK), . . . , o_(o) _(ACK) ⁻¹ ^(ACK) and the encoded HARQ-ACK bits by {tilde over (q)}₀ ^(ACK){tilde over (q)}₁ ^(ACK), . . . , {tilde over (q)}₃₁ ^(ACK),

${{\overset{\sim}{q}}_{i}^{ACK} = {\sum\limits_{n = 0}^{O - 1}\; {\left( {O_{n}^{ACK} \cdot M_{i,n}} \right){mod}\; 2}}},$

where M_(i,n) are basis sequences of an RM code and i=0, 1, . . . , 31. The output bit sequence q₀ ^(ACK), q₁ ^(ACK), q₂ ^(ACK), . . . , q_(Q) _(ACK) ⁻¹ ^(ACK) is obtained by a circular repetition of the bit sequence {tilde over (q)}₀ ^(ACK){tilde over (q)}₁ ^(ACK), . . . , {tilde over (q)}₃₁ ^(ACK), such that the bit sequence length is equal to Q_(ACK), which is the total number of coded HARQ-ACK symbols in a PUSCH.

FIG. 5 is a block diagram illustrating a conventional transmitter for data and HARQ-ACK in a PUSCH.

Referring to FIG. 5, the transmitter includes a data encoder 515, an RM encoder 520, a puncturer/inserter 530, a DFT unit 540, a sub-carrier mapper 550, a selector 555, an IFFT unit 560, a CP inserter 570, and a filter 580 for time windowing. Data information bits 505 and HARQ-ACK information bits 510 are respectively provided to the data encoder 515 and the RM encoder 520. For two HARQ-ACK information bits, a simplex encoder is used instead of the RM encoder 520. Encoded data bits are subsequently punctured and replaced by encoded HARQ-ACK bits by the puncturer/inserter 530. The result is then input to a DFT unit 540. A selector 555 selects REs corresponding to the PUSCH transmission BW for subcarrier mapping in the sub-carrier mapper 550, which are then input to the IFFT unit 560. A CP is inserted by the CP inserter 570, and the CP inserted signal then passes through the filter 580 before being transmitted 590. Again, additional transmitter circuitry is not illustrated for conciseness. Also, the modulation process for the transmitted bits is omitted for brevity.

FIG. 6 is a conventional block diagram illustrating a receiver block for data and HARQ-ACK in a PUSCH.

Referring to FIG. 6, the receiver includes a filter 620 for time windowing, a CP remover 630, an FFT unit 640, a sub-carrier de-mapper 650, a selector 655, an Inverse DFT (IDFT) unit 660, a de-multiplexer 670, a data decoder 680, and an RM decoder 685. After an antenna (not shown) receives a Radio-Frequency (RF) analog signal and further processing units (not shown) convert the analog signal to a digital signal 610, the digital signal 610 passes through the filter 620 and the CP removal unit 630. The output of the CP removal unit 630 is provided to the FFT unit 640, and a selector 655 controls the sub-carrier de-mapper 650 to select the REs used by the transmitter. The obtained values are provided to the IDFT unit 660 and the de-multiplexer 670, which outputs coded data bits, that the coded data bits are then provided to the data decoder 680 and the coded HARQ-ACK bits are then provided to the RM decoder 685 to respectively output data information bits 690 and HARQ-ACK information bits 695. For two HARQ-ACK information bits, a simplex decoder is used instead of the RM decoder 685. Similar to the transmitter illustrated in FIG. 5, receiver functionalities such as channel estimation, demodulation, and decoding are not illustrated in FIG. 6 for brevity.

In order to increase the supportable data rates to a UE, a NodeB can configure multiple cells to a UE in both a DL and a UL to effectively provide higher operating BWs. For example, to support communication over 40 MHz, two 20 MHz cells can be configured to a UE. A UE is always configured a DL cell and a UL cell to maintain communication and each such cell is referred to as Primary cell (Pcell). Additional cells a UE may be configured are referred to as Secondary cells (Scells).

A transmission of HARQ-ACK information can be in a PUCCH of the UL Pcell. For HARQ-ACK multiplexing using channel selection, a separate PUCCH resource is assigned in a UL Pcell for HARQ-ACK signal transmission in response to a PDSCH reception in each subframe of a bundling window and each DL cell.

For two configured cells and a bundling window size of M>1 DL subframes, denoting PUCCH resources associated with reception of PDSCH(s) on the DL Pcell by n_(PUCCH, 0) and n_(PUCCH, 1) and PUCCH resources associated with reception of PDSCH(s) on the Scell and by HARQ-ACK(j), 0≦j≦M−1, by n_(PUCCH, 2) and n_(PUCCH, 3) the ACK/NACK/DTX response for a PDSCH with corresponding DAI value in a PDCCH equal to ‘j+1’, a UE performs channel selection according to Table 4 for M=3 and Table 5 for M=4 and transmits a HARQ-ACK signal using QPSK modulation {b(0),b(1)} on PUCCH resource n_(PUCCH). For the last state in Table 4 and the last two states in Table 5, there is no transmission in a PUCCH, as a UE cannot determine a valid PUCCH resource. The value ‘any’ can be either ‘ACK’ or ‘NACK/DTX’.

TABLE 4 HARQ-ACK Multiplexing with Channel Selection for M = 3 DL Subframes and 2 Configured Cells. Primary Cell Secondary Cell Resource Constellation HARQ-ACK(0), HARQ-ACK(0), n_(PUCCH) b(0), b(1) HARQ-ACK(1), HARQ-ACK(1), HARQ-ACK(2) HARQ-ACK(2) ACK, ACK, ACK ACK, ACK, ACK n_(PUCCH, 1) 1, 1 ACK, ACK, ACK, ACK, ACK n_(PUCCH, 1) 0, 0 NACK/DTX ACK, NACK/ ACK, ACK, ACK n_(PUCCH, 3) 1, 1 DTX, any NACK/DTX, any, ACK, ACK, ACK n_(PUCCH, 3) 0, 1 any ACK, ACK, ACK ACK, ACK, n_(PUCCH, 0) 1, 0 NACK/DTX ACK, ACK, ACK, ACK, n_(PUCCH, 3) 1, 0 NACK/DTX NACK/DTX ACK, NACK/DTX, ACK, ACK, n_(PUCCH, 0) 0, 1 any NACK/DTX NACK/DTX, any, ACK, ACK, n_(PUCCH, 3) 0, 0 any NACK/DTX ACK, ACK, ACK ACK, NACK/DTX, n_(PUCCH, 2) 1, 1 any ACK, ACK, ACK, NACK/DTX, n_(PUCCH, 2) 0, 1 NACK/DTX any ACK, NACK/DTX, ACK, NACK/DTX, n_(PUCCH, 2) 1, 0 any any NACK/DTX, any, ACK, NACK/DTX, n_(PUCCH, 2) 0, 0 any any ACK, ACK, ACK NACK/DTX, any, any n_(PUCCH, 1) 1, 0 ACK, ACK, NACK/DTX, any, any n_(PUCCH, 1) 0, 1 NACK/DTX ACK, NACK/DTX, NACK/DTX, any, any n_(PUCCH, 0) 1, 1 any NACK, any, any NACK/DTX, any, any n_(PUCCH, 0) 0, 0 DTX, any, any NACK/DTX, any, any No Transmission

TABLE 5 HARQ-ACK Multiplexing with Channel Selection for M = 4 DL Subframes and 2 Configured Cells. Primary Cell Secondary Cell Resource Constellation HARQ-ACK(0), HARQ- HARQ-ACK(0), HARQ- n_(PUCCH) b(0), b(1) ACK(1), HARQ-ACK(2), ACK(1), HARQ-ACK(2), HARQ-ACK(3) HARQ-ACK(3) ACK, ACK, ACK, ACK, ACK, ACK, n_(PUCCH, 1) 1, 1 NACK/DTX NACK/DTX ACK, ACK, NACK/DTX, ACK, ACK, ACK, n_(PUCCH, 1) 0, 0 any NACK/DTX ACK, DTX, DTX, DTX ACK, ACK, ACK, n_(PUCCH, 3) 1, 1 NACK/DTX ACK, ACK, ACK, ACK ACK, ACK, ACK, n_(PUCCH, 3) 1, 1 NACK/DTX NACK/DTX, any, any, any ACK, ACK, ACK, n_(PUCCH, 3) 0, 1 NACK/DTX {ACK, NACK/DTX, any, ACK, ACK, ACK, n_(PUCCH, 3) 0, 1 any}, except for {ACK, DTX, NACK/DTX DTX, DTX} ACK, ACK, ACK, ACK, ACK, NACK/DTX, n_(PUCCH, 0) 1, 0 NACK/DTX any ACK, ACK, NACK/DTX, ACK, ACK, NACK/DTX, n_(PUCCH, 3) 1, 0 any any ACK, DTX, DTX, DTX ACK, ACK, NACK/DTX, n_(PUCCH, 0) 0, 1 any ACK, ACK, ACK, ACK ACK, ACK, NACK/DTX, n_(PUCCH, 0) 0, 1 any NACK/DTX, any, any, any ACK, ACK, NACK/DTX, n_(PUCCH, 3) 0, 0 any {ACK, NACK/DTX, any, ACK, ACK, NACK/DTX, n_(PUCCH, 3) 0, 0 any}, except for {ACK, DTX, any DTX, DTX} ACK, ACK, ACK, ACK, DTX, DTX, DTX n_(PUCCH, 2) 1, 1 NACK/DTX ACK, ACK, ACK, ACK, ACK, ACK, ACK n_(PUCCH, 2) 1, 1 NACK/DTX ACK, ACK, NACK/DTX, ACK, DTX, DTX, DTX n_(PUCCH, 2) 0, 1 any ACK, ACK, NACK/DTX, ACK, ACK, ACK, ACK n_(PUCCH, 2) 0, 1 any ACK, DTX, DTX, DTX ACK, DTX, DTX, DTX n_(PUCCH, 2) 1, 0 ACK, DTX, DTX, DTX ACK, ACK, ACK, ACK n_(PUCCH, 2) 1, 0 ACK, ACK, ACK, ACK ACK, DTX, DTX, DTX n_(PUCCH, 2) 1, 0 ACK, ACK, ACK, ACK ACK, ACK, ACK, ACK n_(PUCCH, 2) 1, 0 NACK/DTX, any, any, any ACK, DTX, DTX, DTX n_(PUCCH, 2) 0, 0 NACK/DTX, any, any, any ACK, ACK, ACK, ACK n_(PUCCH, 2) 0, 0 {ACK, NACK/DTX, any, ACK, DTX, DTX, DTX n_(PUCCH, 2) 0, 0 any}, except for {ACK, DTX, DTX, DTX} {ACK, NACK/DTX, any, ACK, ACK, ACK, ACK n_(PUCCH, 2) 0, 0 any}, except for {ACK, DTX, DTX, DTX} ACK, ACK, ACK, NACK/DTX, any, any, any n_(PUCCH, 1) 1, 0 NACK/DTX ACK, ACK, ACK, {ACK, NACK/DTX, any, n_(PUCCH, 1) 1, 0 NACK/DTX any}, except for {ACK, DTX, DTX, DTX} ACK, ACK, NACK/DTX, NACK/DTX, any, any, any n_(PUCCH, 1) 0, 1 any ACK, ACK, NACK/DTX, {ACK, NACK/DTX, any, n_(PUCCH, 1) 0, 1 any any}, except for {ACK, DTX, DTX, DTX} ACK, DTX, DTX, DTX NACK/DTX, any, any, any n_(PUCCH, 0) 1, 1 ACK, DTX, DTX, DTX {ACK, NACK/DTX, any, n_(PUCCH, 0) 1, 1 any}, except for {ACK, DTX, DTX, DTX} ACK, ACK, ACK, ACK NACK/DTX, any, any, any n_(PUCCH, 0) 1, 1 ACK, ACK, ACK, ACK {ACK, NACK/DTX, any, n_(PUCCH, 0) 1, 1 any}, except for {ACK, DTX, DTX, DTX} NACK, any, any, any NACK/DTX, any, any, any n_(PUCCH, 0) 0, 0 NACK, any, any, any {ACK, NACK/DTX, any, n_(PUCCH, 0) 0, 0 any}, except for {ACK, DTX, DTX, DTX} {ACK, NACK/DTX, any, NACK/DTX, any, any, any n_(PUCCH, 0) 0, 0 any}, except for {ACK, DTX, DTX, DTX} {ACK, NACK/DTX, any, {ACK, NACK/DTX, any, n_(PUCCH, 0) 0, 0 any}, except for {ACK, DTX, any}, except for {ACK, DTX, DTX} DTX, DTX, DTX} DTX, any, any, any NACK/DTX, any, any, any No Transmission DTX, any, any, any {ACK, NACK/DTX, any, No Transmission any}, except for {ACK, DTX, DTX, DTX}

For a single-cell operation, HARQ-ACK multiplexing with channel selection conveys a number of HARQ-ACK states in a PUCCH, as described in the example of Table 3 for M=3, while HARQ-ACK transmission in a PUSCH conveys an individual information bit for each DL subframe in a bundling window (or for a number of DL subframes specified by a DAI IE in a UL SA scheduling a PUSCH transmission, if any). Therefore, a maximum of M HARQ-ACK information bits are conveyed. However, if a same approach for HARQ-ACK transmission in a PUSCH were to be followed for multi-cell (DL CA: Down Link Carrier Aggregation) operation, the maximum number of HARQ-ACK information bits would linearly scale with the number of configured cells to a UE. However, increasing the number of HARQ-ACK information bits in a PUSCH for UEs configured HARQ-ACK multiplexing with channel selection in a PUCCH may result in a failure to provide the required HARQ-ACK reception reliability and will often lead to different operations depending on the channel, PUCCH, or PUSCH, used to transmit the HARQ-ACK information.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been designed to solve at least the aforementioned limitations and problems in the prior art and to proved at least the advantages described below.

An aspect of the present invention is to provide a method for transmitting acknowledgement information efficiently in response to data Transport Blocks (TBs) received in one or more downlink data channels in a Time Division Duplex (TDD) communication system.

Another aspect of the present invention is to provide a method for a UE configured with two or more cells in a TDD system to transmit HARQ-ACK information in a PUSCH, when it transmits HARQ-ACK information using multiplexing with channel selection in a PUCCH.

Another aspect of the present invention is to provide a mapping between HARQ-ACK bits transmitted in a PUSCH and the information that these bits represent.

Another aspect of the present invention is to provide a same understanding between a NodeB and a UE of the information represented by HARQ-ACK bits a UE transmits in a PUSCH.

In accordance with an aspect of the present invention, a method for transmitting acknowledgement information in response to data Transport Blocks (TBs) received in one or more downlink data channels by an User Equipment (UE) in a Time Division Duplex (TDD) communication system is provided. The method includes generating acknowledgement information respectively representing a reception result for each data TB by a corresponding acknowledgement bit, if a first condition applies; generating acknowledgement information jointly representing state of reception results for a plurality of data TBs, if a second condition applies; and transmitting the generated acknowledgement information in an uplink data channel.

In accordance with another aspect of the present invention, a User Equipment (UE) for transmitting acknowledgement information in response to data Transport Blocks (TBs) received in one or more downlink data channels in a Time Division Duplex (TDD) communication system is provided. The UE includes a controller for generating acknowledgement information respectively representing a reception result for each data TB by a corresponding acknowledgement bit, if a first condition applies, and generating acknowledgement information jointly representing state of reception results for a plurality of data TBs, if a second condition applies; and a transmitter for transmitting the generated acknowledgement information in an uplink data channel.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram illustrating a conventional TTI for a PUSCH or for a PUCCH;

FIG. 2 is a diagram illustrating a conventional HARQ-ACK transmission structure in a PUCCH subframe slot;

FIG. 3 is a block diagram illustrating a conventional transmitter for a PUCCH;

FIG. 4 is a block diagram illustrating a conventional receiver for a PUCCH;

FIG. 5 is a block diagram illustrating a conventional transmitter for data and HARQ-ACK in a PUSCH;

FIG. 6 is a block diagram illustrating a conventional receiver for data and HARQ-ACK in a PUSCH;

FIG. 7 is a flowchart illustrating a method of identifying HARQ-ACK bit representation depending on a number of configured cells and on a value of a bundling window, according to an embodiment of the present invention;

FIG. 8 is a flowchart illustrating an encoding and decoding process of HARQ-ACK information for a UE configured with two cells, depending on a value of a bundling window, according to an embodiment of the present invention;

FIG. 9 is a flowchart illustrating an encoding and decoding process of HARQ-ACK states, depending on whether a transmission is in a PUCCH or in a PUSCH, for M=3 or M=4 subframes, according to an embodiment of the present invention;

FIG. 10 is a block diagram illustrating a transmitter for transmitting data and HARQ-ACK information in a PUSCH, according to an embodiment of the present invention; and

FIG. 11 is a block diagram illustrating a receiver for receiving data and HARQ-ACK information in a PUSCH, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Various embodiments of the present invention will now be described more fully hereinafter with reference to the accompanying drawings. This present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the present invention to those skilled in the art.

Additionally, although embodiments of the present invention will be described below with reference to DFT-spread OFDM transmission, the present invention is also applicable to Frequency Division Multiplexing (FDM) transmissions, such as Single-Carrier Frequency Division Multiple Access (SC-FDMA) and OFDM.

In the following descriptions for HARQ-ACK transmission in a PUSCH, the value of M (i.e., a number of PDSCHs for which a UE provides HARQ-ACK information or a size of bundling window or a number of TTIs) can either be fixed, as defined by a bundling window size for a particular configuration of a TDD system, or be variable, as defined by a value of a DAI IE in a UL SA conveyed by a PDCCH scheduling a PUSCH transmission, if such a UL SA exists. Further, although for simplicity is the descriptions assume that HARQ-ACK information is generated in response to a PDSCH reception, the HARQ-ACK information may also be generated in response to a PDCCH that does not schedule a PDSCH reception, but instead indicates a release of a Semi-Persistently Scheduled (SPS) PDSCH.

In accordance with an embodiment of the present invention, a UE is configured with two DL cells (the Pcell and a Scell) in a TDD system and mapping of HARQ-ACK states is performed as shown in Tables 4 and 5 (for M=3 and M=4, respectively) to input bits of an RM code used for encoding HARQ-ACK information in a PUSCH. This mapping is performed under the constraint that the number of HARQ-ACK information bits input to an RM code is limited to four, as HARQ-ACK multiplexing with channel selection in a PUCCH is assumed to be supported for only up to four HARQ-ACK information bits conveying different HARQ-ACK states. That is, two bits are conveyed through the selection of a PUCCH resource among four available resources, and another two bits are conveyed through a QPSK modulated signal by the respective constellation points.

Unlike conventional HARQ-ACK transmission in a PUSCH, where each HARQ-ACK information bit represents the outcome of respective data TB reception(s) in a PDSCH, in accordance with an embodiment of the present invention, the mapping of HARQ-ACK information to four input bits of an RM encoder for the above operating scenario includes HARQ-ACK states (a HARQ-ACK state is a set of correct or incorrect detection outcomes for data TBs) conveying combinations for values of HARQ-ACK bits as shown in Tables 4 and 5. Therefore, all four HARQ-ACK information bits are jointly considered and an individual HARQ-ACK bit does not have a respective individual interpretation (as it does not indicate an individual correct or incorrect detection outcome for data TBs). This alternative representation is used because the four input bits to an RM code do not suffice to represent all possible combinations for the individual outcomes of data TB reception(s) in each PDSCH in two cells for M=3 or M=4 (i.e., 6 or 8 bits, respectively, would be needed).

Conversely, for M=2, four input bits to an RM encoder can provide individual HARQ-ACK information about the outcome of data TB reception(s) in a PDSCH for each respective subframe of a bundling window and for each of the two cells (Pcell and Scell). For example, two of the four bits can be used to represent HARQ-ACK information for the Pcell and the other two can be used to represent HARQ-ACK information for the Scell with the first of the two bits corresponding to the first of the M=2 subframes and the second of the two bits corresponding to the second of the M=2 subframes. For M=1, two input bits to an RM encoder can provide individual HARQ-ACK information about the outcome a PDSCH reception in the Pcell and the Scell, respectively.

FIG. 7 is a flowchart illustrating a method of identifying HARQ-ACK bit representation depending on a number of configured cells and on a value of a bundling window, according to an embodiment of the present invention.

Referring to FIG. 7, for a PUSCH transmitter and a PUSCH receiver, the meaning of HARQ-ACK information bits in a PUSCH depends on whether a UE is configured one or two cells in step 710. If a UE is configured one cell, in step 720, the PUSCH transmitter or receiver determines that each HARQ-ACK information bit represents an outcome (e.g., ACK for binary ‘1’ or NACK/DTX for binary ‘0’) for a reception of TB(s) in a corresponding PDSCH, regardless of the value of M. This assumes that HARQ-ACK spatial-domain bundling applies if a PDSCH conveys multiple TBs, that a DTX state and a NACK state are jointly represented, and the explicit DTX feedback is not supported in a PUSCH; however, the reverse may also apply.

If a UE is configured two cells, the representation of HARQ-ACK information bits depends on the value of M in step 730. If M is smaller than or equal to 2, in step 740, the PUSCH transmitter or receiver determines that each HARQ-ACK information bit again represents an outcome (ACK for binary ‘1’ or NACK/DTX for binary ‘0’) for a reception of TB(s) in a corresponding PDSCH. However, if M is larger than 2, in step 750, the PUSCH transmitter or receiver determines that each HARQ-ACK information bit does not provide any information on its own and all HARQ-ACK information bits are jointly considered to indicate a HARQ-ACK state (set of outcomes for correct or incorrect detection of data TB(s) in respective PDSCH(s)) corresponding to both cells and all PDSCHs for which HARQ-ACK information is provided by a UE.

In accordance with another embodiment of the present invention, HARQ-ACK states, as represented in Tables 4 and 5, are transmitted in a PUCCH using channel selection, by the four input bits {o₀ ^(ACK)o₁ ^(ACK)o₂ ^(ACK)o₃ ^(ACK)} to an RM encoder for transmission in a PUSCH. This representation is obtained by one-to-one mapping of a PUCCH resource and a constellation point of a QPSK modulation of a HARQ-ACK signal in a PUCCH to four input bits {o₀ ^(ACK)o₁ ^(ACK)o₂ ^(ACK)o₃ ^(ACK)} of an RM code in a PUSCH, e.g., as shown in Table 6 for M=3 and in Table 7 for M=4.

For example, the first four PUCCH resources {n_(PUCCH, 0), n_(PUCCH, 1), n_(PUCCH, 2), n_(PUCCH, 3)} may be represented by RM input bits {o₀ ^(ACK) or o₁ ^(ACK)} and the four QPSK constellation points {(0,0), (0,1), (1,0), (1,1)} in a PUCCH may be represented by RM input bits {o₂ ^(ACK)o₃ ^(ACK)}. In general, any representation of any two RM input bits for four PUCCH resources and of the other two RM input bits for the QPSK constellation points in a PUCCH may be used.

TABLE 6 Mapping of HARQ-ACK States to Input Bits of the RM Code for M = 3. RM Code Input Primary Cell Secondary Cell Resource Constellation Bits HARQ-ACK(0), HARQ-ACK(0), n_(PUCCH) b(0), b(1) {o₀ ^(ACK) o₁ ^(ACK) o₂ ^(ACK) o₃ ^(ACK)} HARQ-ACK(1), HARQ-ACK(1), HARQ-ACK(2) HARQ-ACK(2) ACK, ACK, ACK ACK, ACK, ACK n_(PUCCH, 1) 1, 1 0, 1, 1, 1 ACK, ACK, ACK, ACK, ACK n_(PUCCH, 1) 0, 0 0, 1, 0, 0 NACK/DTX ACK, ACK, ACK, ACK n_(PUCCH, 3) 1, 1 1, 1, 1, 1 NACK/DTX, any NACK/DTX, any, ACK, ACK, ACK n_(PUCCH, 3) 0, 1 1, 1, 0, 1 any ACK, ACK, ACK ACK, ACK, n_(PUCCH, 0) 1, 0 0, 0, 1, 0 NACK/DTX ACK, ACK, ACK, ACK, n_(PUCCH, 3) 1, 0 1, 1, 1, 0 NACK/DTX NACK/DTX ACK, ACK, ACK, n_(PUCCH, 0) 0, 1 0, 0, 0, 1 NACK/DTX, any NACK/DTX NACK/DTX, any, ACK, ACK, n_(PUCCH, 3) 0, 0 1, 1, 0, 0 any NACK/DTX ACK, ACK, ACK ACK, n_(PUCCH, 2) 1, 1 1, 0, 1, 1 NACK/DTX, any ACK, ACK, ACK, n_(PUCCH, 2) 0, 1 1, 0, 0, 1 NACK/DTX NACK/DTX, any ACK, ACK, n_(PUCCH, 2) 1, 0 1, 0, 1, 0 NACK/DTX, any NACK/DTX, any NACK/DTX, any, ACK, n_(PUCCH, 2) 0, 0 1, 0, 0, 0 any NACK/DTX, any ACK, ACK, ACK NACK/DTX, any, n_(PUCCH, 1) 1, 0 0, 1, 1, 0 any ACK, ACK, NACK/DTX, any, n_(PUCCH, 1) 0, 1 0, 1, 0, 1 NACK/DTX any ACK, NACK/DTX, any, n_(PUCCH, 0) 1, 1 0, 0, 1, 1 NACK/DTX, any any NACK, any, any NACK/DTX, any, n_(PUCCH, 0) 0, 0 0, 0, 0, 0 any DTX, any, any NACK/DTX, any, No Transmission 0, 0, 0, 0 any

TABLE 7 Mapping of HARQ-ACK States to Input Bits of the RM Code for M = 4. Primary Cell Secondary Cell Resource Constellation RM Code Input Bits HARQ-ACK(0), HARQ-ACK(0), n_(PUCCH) b(0), b(1) {o₀ ^(ACK) o₁ ^(ACK) o₂ ^(ACK) o₃ ^(ACK)} HARQ-ACK(1), HARQ-ACK(1), HARQ-ACK(2), HARQ-ACK(2), HARQ-ACK(3) HARQ-ACK(3) ACK, ACK, ACK, ACK, ACK, ACK, n_(PUCCH, 1) 1, 1 0, 1, 1, 1 NACK/DTX NACK/DTX ACK, ACK, ACK, ACK, ACK, n_(PUCCH, 1) 0, 0 0, 1, 0, 0 NACK/DTX, any NACK/DTX ACK, DTX, DTX, ACK, ACK, ACK, n_(PUCCH, 3) 1, 1 1, 1, 1, 1 DTX NACK/DTX ACK, ACK, ACK, ACK, ACK, ACK, n_(PUCCH, 3) 1, 1 1, 1, 1, 1 ACK NACK/DTX NACK/DTX, any, any, ACK, ACK, ACK, n_(PUCCH, 3) 0, 1 1, 1, 0, 1 any NACK/DTX {ACK, NACK/DTX, ACK, ACK, ACK, n_(PUCCH, 3) 0, 1 1, 1, 0, 1 any, any}, except for NACK/DTX {ACK, DTX, DTX, DTX} ACK, ACK, ACK, ACK, ACK, n_(PUCCH, 0) 1, 0 0, 0, 1, 0 NACK/DTX NACK/DTX, any ACK, ACK, ACK, ACK, n_(PUCCH, 3) 1, 0 1, 1, 1, 0 NACK/DTX, any NACK/DTX, any ACK, DTX, DTX, ACK, ACK, n_(PUCCH, 0) 0, 1 0, 0, 0, 1 DTX NACK/DTX, any ACK, ACK, ACK, ACK, ACK, n_(PUCCH, 0) 0, 1 0, 0, 0, 1 ACK NACK/DTX, any NACK/DTX, any, any, ACK, ACK, n_(PUCCH, 3) 0, 0 1, 1, 0, 0 any NACK/DTX, any {ACK, NACK/DTX, ACK, ACK, n_(PUCCH, 3) 0, 0 1, 1, 0, 0 any, any}, except for NACK/DTX, any {ACK, DTX, DTX, DTX} ACK, ACK, ACK, ACK, DTX, DTX, n_(PUCCH, 2) 1, 1 1, 0, 1, 1 NACK/DTX DTX ACK, ACK, ACK, ACK, ACK, ACK, n_(PUCCH, 2) 1, 1 1, 0, 1, 1 NACK/DTX ACK ACK, ACK, ACK, DTX, DTX, n_(PUCCH, 2) 0, 1 1, 0, 0, 1 NACK/DTX, any DTX ACK, ACK, ACK, ACK, ACK, n_(PUCCH, 2) 0, 1 1, 0, 0, 1 NACK/DTX, any ACK ACK, DTX, DTX, ACK, DTX, DTX, n_(PUCCH, 2) 1, 0 1, 0, 1, 0 DTX DTX ACK, DTX, DTX, ACK, ACK, ACK, n_(PUCCH, 2) 1, 0 1, 0, 1, 0 DTX ACK ACK, ACK, ACK, ACK, DTX, DTX, n_(PUCCH, 2) 1, 0 1, 0, 1, 0 ACK DTX ACK, ACK, ACK, ACK, ACK, ACK, n_(PUCCH, 2) 1, 0 1, 0, 1, 0 ACK ACK NACK/DTX, any, any, ACK, DTX, DTX, n_(PUCCH, 2) 0, 0 1, 0, 0, 0 any DTX NACK/DTX, any, any, ACK, ACK, ACK, n_(PUCCH, 2) 0, 0 1, 0, 0, 0 any ACK {ACK, NACK/DTX, ACK, DTX, DTX, n_(PUCCH, 2) 0, 0 1, 0, 0, 0 any, any}, except for DTX {ACK, DTX, DTX, DTX} {ACK, NACK/DTX, ACK, ACK, ACK, n_(PUCCH, 2) 0, 0 1, 0, 0, 0 any, any}, except for ACK {ACK, DTX, DTX, DTX} ACK, ACK, ACK, NACK/DTX, any, n_(PUCCH, 1) 1, 0 0, 1, 1, 0 NACK/DTX any, any ACK, ACK, ACK, {ACK, NACK/DTX, n_(PUCCH, 1) 1, 0 0, 1, 1, 0 NACK/DTX any, any}, except for {ACK, DTX, DTX, DTX} ACK, ACK, NACK/DTX, any, n_(PUCCH, 1) 0, 1 0, 1, 0, 1 NACK/DTX, any any, any ACK, ACK, {ACK, NACK/DTX, n_(PUCCH, 1) 0, 1 0, 1, 0, 1 NACK/DTX, any any, any}, except for {ACK, DTX, DTX, DTX} ACK, DTX, DTX, NACK/DTX, any, n_(PUCCH, 0) 1, 1 0, 0, 1, 1 DTX any, any ACK, DTX, DTX, {ACK, NACK/DTX, n_(PUCCH, 0) 1, 1 0, 0, 1, 1 DTX any, any}, except for {ACK, DTX, DTX, DTX} ACK, ACK, ACK, NACK/DTX, any, n_(PUCCH, 0) 1, 1 0, 0, 1, 1 ACK any, any ACK, ACK, ACK, {ACK, NACK/DTX, n_(PUCCH, 0) 1, 1 0, 0, 1, 1 ACK any, any}, except for {ACK, DTX, DTX, DTX} NACK, any, any, any NACK/DTX, any, n_(PUCCH, 0) 0, 0 0, 0, 0, 0 any, any NACK, any, any, any {ACK, NACK/DTX, n_(PUCCH, 0) 0, 0 0, 0, 0, 0 any, any}, except for {ACK, DTX, DTX, DTX} {ACK, NACK/DTX, NACK/DTX, any, n_(PUCCH, 0) 0, 0 0, 0, 0, 0 any, any}, except for any, any {ACK, DTX, DTX, DTX} {ACK, NACK/DTX, {ACK, NACK/DTX, n_(PUCCH, 0) 0, 0 0, 0, 0, 0 any, any}, except for any, any}, except for {ACK, DTX, DTX, {ACK, DTX, DTX, DTX} DTX} DTX, any, any, any NACK/DTX, any, No Transmission 0, 0, 0, 0 any, any DTX, any, any, any {ACK, NACK/DTX, No Transmission 0, 0, 0, 0 any, any}, except for {ACK, DTX, DTX, DTX}

Conversely, the representation of HARQ-ACK states to four input bits {o₀ ^(ACK)o₁ ^(ACK)o₂ ^(ACK)o₃ ^(ACK)} of an RM encoder for M=2 is obtained as shown in Table 8 below. Each individual HARQ-ACK bit now provides individual information with a binary ‘1’ representing an ‘ACK’ and a binary ‘0’ representing a ‘NACK/DTX’ for a corresponding PDSCH reception. There is no link between the four input bits {o₀ ^(ACK)o₁ ^(ACK)o₂ ^(ACK)o₃ ^(ACK)} of an RM code for HARQ-ACK transmission in a PUSCH and the PUCCH resources or the constellation point of a QPSK modulated signal for HARQ-ACK in a PUCCH. Similar observations apply for the representation of HARQ-ACK states to the two input bits {o₀ ^(ACK)o₁ ^(ACK)} of a simplex (3, 2) code for M=1, which is obtained as shown in Table 9.

TABLE 8 Mapping of HARQ-ACK States to Input Bits of the RM Code for M = 2. RM Code Input Primary Cell Secondary Cell Bits HARQ-ACK(0), HARQ-ACK(0), {o₀ ^(ACK) o₁ ^(ACK) o₂ ^(ACK) o₃ ^(ACK)} HARQ-ACK(1) HARQ-ACK(1) ACK, ACK ACK, ACK 1, 1, 1, 1 ACK, NACK/DTX ACK, ACK 1, 0, 1, 1 NACK/DTX, ACK ACK, ACK 0, 1, 1, 1 NACK/DTX, ACK, ACK 0, 0, 1, 1 NACK/DTX ACK, ACK ACK, NACK/DTX 1, 1, 1, 0 ACK, NACK/DTX ACK, NACK/DTX 1, 0, 1, 0 NACK/DTX, ACK ACK, NACK/DTX 0, 1, 1, 0 NACK/DTX, ACK, NACK/DTX 0, 0, 1, 0 NACK/DTX ACK, ACK NACK/DTX, ACK 1, 1, 0, 1 ACK, NACK/DTX NACK/DTX, ACK 1, 0, 0, 1 NACK/DTX, ACK NACK/DTX, ACK 0, 1, 0, 1 NACK/DTX, NACK/DTX, ACK 0, 0, 0, 1 NACK/DTX ACK, ACK NACK/DTX, 1, 1, 0, 0 NACK/DTX ACK, NACK/DTX NACK/DTX, 1, 0, 0, 0 NACK/DTX NACK/DTX, ACK NACK/DTX, 0, 1, 0, 0 NACK/DTX NACK/DTX, NACK/DTX, 0, 0, 0, 0 NACK/DTX NACK/DTX

TABLE 9 Mapping of HARQ-ACK States to Input Bits of the Simplex Code for M = 1. Simplex Code Input Primary Cell Secondary Cell Bits HARQ-ACK(0) HARQ-ACK(0) {o₀ ^(ACK) o₁ ^(ACK)} ACK ACK 1, 1 NACK/DTX ACK 0, 1 ACK NACK/DTX 1, 0 NACK/DTX NACK/DTX 0, 0

FIG. 8 illustrates encoding and decoding of HARQ-ACK information for a UE configured with two cells depending on a value of a bundling window, according to an embodiment of the present invention.

Referring to FIG. 8, the encoding and decoding for a UE configured with two cells and for a PUSCH transmitter and a PUSCH receiver, respectively, depends on a value of M in step 810. If M is less than two, in step 820, each HARQ-ACK information bit represents an outcome (e.g., ACK or NACK/DTX) of a respective PDSCH reception. However, if M is greater than two, in step 830, each HARQ-ACK information bit does not provide individual information; instead, all four HARQ-ACK information bits are jointly considered to represent a HARQ-ACK state (set of outcomes for correct or incorrect detection of data TB(s) in respective PDSCH(s)) for the Pcell and a HARQ-ACK state for the Scell using a mapping as shown in Table 6 for M=3 or a mapping as shown in Table 7 for M=4.

In accordance with another embodiment of the present invention, a same understanding is established between a UE and a serving NodeB for the inclusion of HARQ-ACK information in a PUSCH. Consequently, a serving NodeB is not required to detect whether a particular set of PUSCH REs conveys data information or HARQ-ACK information, because such detection may not be reliable. For HARQ-ACK signal transmission in a PUCCH, such detection is relatively simple as a NodeB can decide whether a signal is transmitted or not by merely computing the received energy in candidate PUCCH resources.

If a PUSCH transmission is scheduled by a UL SA through the transmission of a corresponding PDCCH, the respective DCI format is assumed to include a DAI IE informing a UE whether or not a NodeB expects it to transmit HARQ-ACK information in a PUSCH. This DAI IE may also provide additional information, e.g., the maximum number of PDSCH transmitted to a UE either in the Pcell or in the Scell, and the value of M can be set equal to this number. If a PUSCH transmission is SPS and not scheduled by a UL SA, then a UE may include HARQ-ACK information in a PUSCH for all DL subframes in a bundling window. M is then equal to the bundling window size.

In order to include HARQ-ACK information in a PUSCH (when a NodeB expects a UE to transmit HARQ-ACK information in a PUSCH), the HARQ-ACK states as shown in Tables 4 or 5, for which a UE does not transmit a HARQ-ACK signal in a PUCCH, should be mapped to actual HARQ-ACK information bits in a PUSCH, when M=3 and M=4.

For M=3, the last state in Table 4 is overlapped with the second to last state in Table 6 and both are represented by {0, 0, 0, 0} input bits to an RM encoder. Similarly, for M=4, the last two states in Table 5 are overlapped with the {NACK, any, any, any} and the {NACK/DTX, any, any, any} states in Table 7 for the Pcell and the Scell, respectively, and are represented by {0, 0, 0, 0} input bits to an RM encoder.

FIG. 9 illustrates an encoding and decoding process of HARQ-ACK states depending on whether a transmission is in a PUCCH or in a PUSCH for M=3 or M=4 subframes, according to an embodiment of the present invention.

Referring to FIG. 9, the encoding and decoding of the {DTX, any, any} state in the Pcell and of the {NACK/DTX, any, any} state in the Scell for M=3 in step 910, and the encoding and decoding of the {DTX, any, any, any} state in the Pcell and of the {NACK/DTX, any, any, any} or the {ACK, NACK/DTX, any, any} state (except for {ACK, DTX, DTX, DTX} state) in the Scell for M=4 in step 920 depends on whether HARQ-ACK information is to be transmitted in a PUCCH or in a PUSCH in step 930. When HARQ-ACK information is to be transmitted in a PUCCH, there is no HARQ-ACK signal transmission for these HARQ-ACK states in step 940. When HARQ-ACK information is to be transmitted in a PUSCH, {0, 0, 0, 0} bits are used to represent these HARQ-ACK states in step 950.

FIG. 10 illustrates block diagram of a transmitter for data and HARQ-ACK in a PUSCH, according to an embodiment of the present invention. Specifically, in FIG. 10, a representation of HARQ-ACK information bits depends on the number of cells a UE is configured and on whether each HARQ-ACK information bit informs of an outcome for a respective PDSCH reception in a respective cell or whether all HARQ-ACK information bits jointly inform of HARQ-ACK states corresponding to M PDSCH receptions in both cells.

Referring to FIG. 10, if a UE is configured with one cell or if a UE is configured with two cells and it is M≦2, each HARQ-ACK information bit corresponds to an outcome (ACK or NACK/DTX) of a respective PDSCH reception as described with reference to FIG. 5. However, if a UE is configured with two cells and M>2, a UE transmitter as illustrated in FIG. 10 operates similarly to the transmitter of FIG. 5, except that the outcomes for M PDSCH receptions (combinations of ACK and NACK/DTX) for each of the two cells 1010 form two respective HARQ-ACK states, which are provided to a mapper 1020, as described for example in Table 6 for M=3 and Table 7 for M=4, which then generates the HARQ-ACK information bits 1030, which are provided to an RM encoder.

FIG. 11 illustrates a block diagram of a receiver for data and HARQ-ACK in a PUSCH, according to an embodiment of the present invention. Specifically, in FIG. 11, a representation of HARQ-ACK information bits depends on the number of cells a UE is configured and on whether each HARQ-ACK information bit informs of an outcome for a respective PDSCH reception in a respective cell or whether all HARQ-ACK information bits jointly inform of HARQ-ACK states corresponding to M PDSCH receptions in both cells.

Referring to FIG. 11, if a UE is configured with one cell or if a UE is configured with two cells and it is M≦2, each HARQ-ACK information bit corresponds to an outcome (ACK or NACK/DTX) of a respective PDSCH reception, as described with reference to FIG. 6. However, if a UE is configured with two cells and M>2, a NodeB receiver as illustrated in FIG. 11 operates similarly to the receiver illustrated in FIG. 6, except that a decoder output for HARQ-ACK information bits 1110 is provided to a mapper 1120, e.g., as described in Table 6 for M=3 or Table 7 for M=4, which then generates two HARQ-ACK states representing outcomes 1130 for M PDSCH receptions (combinations of ACK and NACK/DTX) for each of the two cells.

One or more blocks in a transmitter and a receiver described in embodiments of the present invention can be implemented into a controller and the controller generates or receives acknowledgement bits (i.e. acknowledgement information) according to the present invention.

While the present invention has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims and their equivalents. 

1. A method for transmitting acknowledgement information in response to data Transport Blocks (TBs) received in one or more downlink data channels by an User Equipment (UE) in a Time Division Duplex (TDD) communication system, the method comprising the steps of: generating acknowledgement information respectively representing a reception result for each data TB by a corresponding acknowledgement bit, if a first condition applies; generating acknowledgement information jointly representing state of reception results for a plurality of data TBs, if a second condition applies; and transmitting the generated acknowledgement information in an uplink data channel.
 2. The method of claim 1, wherein the first condition includes a condition that a size of bundling window is one or two and the bundling window denotes a number of downlink sub-frames in which the plurality of data TBs are transmitted.
 3. The method of claim 1, wherein the first condition includes a condition that a size of bundling window is three or four and the bundling window denotes a number of downlink sub-frames in which the plurality of data TBs are transmitted.
 4. The method of claim 1, wherein the first condition is applied when the UE is configured for reception of the downlink data channels from a single cell, and the second condition is applied when the UE is configured for reception of the downlink data channels from a plurality of cells.
 5. The method of claim 1, wherein the acknowledgement information is generated at each TTI(Transmission Time Interval).
 6. The method of claim 1, wherein the first condition includes the UE being configured for reception of the downlink data channels from a single cell, or the UE being configured for reception of the downlink data channels from two cells and a number of the TTIs being one or two.
 7. The method of claim 1, wherein the second condition includes the UE being configured for reception of the downlink data channels from two cells and a number of the TTIs being three or four.
 8. The method of claim 1, wherein a single outcome is generated by the UE, when the UE receives more than one data TB in the downlink data channel, and wherein the single outcome indicates correct detection, if all of the data TBs were correctly detected, and indicates incorrect detection, if at least one of the data TBs was incorrectly detected by the UE.
 9. The method of claim 1, wherein when the UE does not detect a data TB or a control channel releasing transmission of the downlink data channel in a TTI, the UE generates a single outcome indicating the incorrect detection.
 10. The method of claim 1, wherein when the acknowledgement information is transmitted in an uplink control channel, the acknowledgement information is generated by using bits indicating resources of the uplink control channel and bits indicating a constellation point of the uplink control channel.
 11. A User Equipment (UE) for transmitting acknowledgement information in response to data Transport Blocks (TBs) received in one or more downlink data channels in a Time Division Duplex (TDD) communication system, the apparatus comprising: a controller for generating acknowledgement information respectively representing a reception result for each data TB by a corresponding acknowledgement bit, if a first condition applies, and generating acknowledgement information jointly representing state of reception results for a plurality of data TBs, if a second condition applies; and a transmitter for transmitting the generated acknowledgement information in an uplink data channel.
 12. The UE of claim 11, wherein the first condition includes a condition that a size of bundling window is one or two and the bundling window denotes a number of downlink sub-frames in which the plurality of data TBs are transmitted.
 13. The UE of claim 11, wherein the first condition includes a condition that a size of bundling window is three or four and the bundling window denotes a number of downlink sub-frames in which the plurality of data TBs are transmitted.
 14. The UE of claim 11, wherein the first condition is applied when the UE is configured for reception of the downlink data channels from a single cell, and the second condition is applied when the UE is configured for reception of the downlink data channels from a plurality of cells.
 15. The UE of claim 11, wherein the acknowledgement information is generated at each TTI(Transmission Time Interval).
 16. The UE of claim 11, wherein the first condition includes the UE being configured for reception of the downlink data channels from a single cell, or the UE being configured for reception of the downlink data channels from two cells and a number of the TTIs being one or two.
 17. The UE of claim 11, wherein the second condition includes the UE being configured for reception of the downlink data channels from two cells and a number of the TTIs being three or four.
 18. The UE of claim 11, wherein the controller generates a single outcome, when the UE receives more than one data TB in the downlink data channel, and wherein the controller represents the single outcome to indicate correct detection, if all of the data TBs were correctly detected, and to indicate incorrect detection, if at least one of the data TBs was incorrectly detected.
 19. The UE of claim 11, wherein when the controller does not detect a data TB or a control channel releasing transmission of the downlink data channel in a TTI, the controller generates a single outcome indicating incorrect detection as the acknowledgement information.
 20. The UE of claim 11, wherein when the acknowledgement information is transmitted in an uplink control channel, the controller generates the acknowledgement information by using bits indicating resources of the uplink control channel and bits indicating a constellation point of the uplink control channel. 